JPH0518824Y2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention [Field of industrial application] This invention relates to a cased pneumatic switch.

[Prior Art] Conventionally, in a case-filled pneumatic switch in which a movable contact blade is rotatably provided and the movable contact blade is opened and closed, the movable contact blade is formed in an L-shape. As a result, the switch becomes large, which poses a problem when trying to make it smaller and lighter.

Additionally, if you want to increase the rated load switching capacity of a switch, the arc extinguishing chamber placed on the fixed electrode side must be made larger to increase the arc extinguishing capacity. There was a problem with the conversion.

In order to solve this problem, the applicant filed a
-160877 (Utility Model Publication No. 60-69442) is proposed. This switch has bushings for each phase fixed through the switch case, and a fixed electrode is provided at the inner end of one of the bushings on the power supply side or load side.
A straight movable contact blade is rotatably attached to the other bushing. An arc extinguishing chamber that covers the fixed electrode is provided on the inner end side of the bushing, and the arc extinguishing chamber is connected to a fixed electrode storage chamber that stores the fixed electrode and a fixed electrode storage chamber to perform fine arc extinguishing. It consists of small rooms. A U-shaped arc driving piece is provided on the outer periphery of the arc extinguishing chamber to drive an arc generated between the movable contact blade and the fixed electrode toward the side surface of the arc extinguishing chamber when the movable electrode is opened.

This switch is excellent in that the rotation locus of the movable contact blade can be reduced, the arc extinguishing ability of the arc extinguishing chamber can be increased, and the size of the arc extinguishing chamber itself can be reduced.

However, there is a need for something that can go beyond these advantages and reduce the size of the arc extinguishing chamber itself.

[Problems to be solved by the invention] This invention attempts to solve the problem of the arc extinguishing ability of the movable contact blade and the arc extinguishing chamber, which have a large rotation locus in the above-mentioned cased switch. This is an attempt to improve Utility Application No. 160877, 1983, which was filed earlier by

Structure of the invention [Means for solving the problem] This invention penetrates and fixes bushings facing each other for each phase in the switch case, and the inner end of a conductive rod inserted into one bushing is A fixed electrode is fixedly fixed thereto, and a straight movable contact blade is rotatably attached to the inner end of a conductive rod inserted into the other bushing to be attached to and separated from the fixed electrode,
An arc extinguishing chamber that covers the fixed electrode is fixed to the inner end of the conductive rod of one bushing, and the arc extinguishing chamber communicates with the fixed electrode storage chamber that stores the fixed electrode and the fixed electrode storage chamber. It consists of a small arc extinguishing chamber that performs arcing, and the end of the fixed electrode storage chamber on the insertion direction side of the movable contact blade and the end of the movable contact blade on the insertion direction side so that the area of the inner surface of the arc extinguishing small chamber is widened. The arc extinguishing narrow chamber is connected obliquely to the movable contact blade side side of the narrow arc extinguishing chamber to form an opening that allows the movable contact blade to be inserted into and released from the arc extinguishing chamber. A U-shaped arc driving piece is provided to drive the arc generated between the movable contact blade and the fixed electrode to the inner side surface of the arc extinguishing chamber when opened.

[Function] With the above solution, when an arc occurs between both electrodes, a magnetic flux along the arc driving piece and a magnetic flux perpendicular to the arc current are generated in the arc driving piece, and the arc is extinguished by the magnetic force of both magnetic fluxes. The arc is forcibly moved to the closing part of the narrow arc chamber and expanded, and the arc is extinguished by the arc extinguishing gas generated in the narrow arc chamber. Since the area of the inner surface of the arc-extinguishing narrow output is widened, the contact area of the arc is added when the arc occurs, improving the cooling and arc-extinguishing ability. By being pushed into the chamber, deionization takes place efficiently on the cold walls. As a result, the arc generated between the fixed electrode and the movable contact blade can be effectively directed toward the bushing side of the narrow arc extinguishing chamber.

Furthermore, by reducing the rotation locus of the movable contact blade, attaching the fixed electrode and movable contact blade directly to the inner end of the bushing, and by increasing the arc extinguishing ability of the arc extinguishing chamber, the switch can be made lighter and more compact. be able to.

[Example] An example in which this invention is applied to an air load switch with an overcurrent lock will be described below with reference to Figures 1 to 9. Packing 2 is provided at the lower part of the periphery. A bottom lid 3 is attached to and removed from the lower opening of the main body case 1 to open and close the opening, and when the bottom lid 3 is attached and closed, a bend formed on the outer circumference of the bottom lid 3 portion is pressed against the packing 2.

Upper fixing fittings 4 and 5 are fixed at multiple locations on the outer periphery of the lower end of the main body case 1;
The fixing portions 6 and 7 are bent and formed to extend outward, and the leg portions 8 extend downward and function as legs for the entire case.
Lower fixing fittings 9, 10 corresponding to the fixing parts 6, 7 are fixed to the bottom surface of the bottom cover 3, and bolts are inserted through both the upper and lower fixing fittings 4, 5, 9, 10 and the spacer 11 interposed therebetween. 12 is Natsu 1
It is closed by being tightened to 3.

A circular hanging ring 14 is loosely inserted between the fixing part 6 of one of the upper fixing brackets 4 and the tip of the lower fixing bracket 9, so that when the bottom cover 3 is removed from the main body case 1, Hang 3.

A mounting bracket 15 is provided on the upper surface of the case of the main body 1 to be attached to a armrest (not shown), and bushings 16 and 17 for each phase are penetrated and fixed in an airtight manner on each side of the case so as to face each other. It is set up.

A conductive rod 1 is provided in the inner cavity of the bushings 16 and 17.
8 is inserted and attached, and the lead wire 19 is caulked to the outer end of the conductive rod 18, and the diameter-reduced threaded portion 20 is attached to the inner end of the bushing 16, 17.
It is formed to protrude from the inner end. In addition,
As shown in FIG. 2, the threaded portion 20 is formed into a drum-shaped cross section so that both sides thereof are flat.

A shield member 21 formed into a cylinder with a bottom and made of nonferrous metal, rubber, synthetic resin, etc. is inserted into the inner end of the conductive rod 18, and a nut (not shown) screwed into the threaded portion 20 is tightened. The shield member 21 is fastened and fixed to the inner end surfaces of the bushings 16 and 17.

Threaded portion 2 of conductive rod 18 of one bushing 16
A pair of fixed contact pieces 22 are attached to bolts 23 on both sides of the
The fixed electrode 24 is configured by being tightened and fixed.

The fixed contact piece 22 has a contact part 25 whose tip is divided into two and extends downward, and the contact part 25a on the bushing 16 side extends downward longer than the other contact part 25b. The entire tip portion of the bushing 17 is formed obliquely toward the bushing 17 side. Furthermore, the threaded portion 20 of the conductive rod 18 is attached to the outer surface of the contact portion 25 by the bolt 23.
The tip of a pressing spring 26 fixed to the contact portion 25 is brought into contact with the contact portion 25a, 25b to urge the contact portions 25a and 25b in the sandwiching direction.

Further, on one side of the threaded portion 20 of the conductive rod 18 of the bushing 16, a mounting ridge 28 formed on the lower surface of the arc-extinguishing chamber mounting plate 27 is disposed along the mounting ridge 28. The arc-extinguishing chamber mounting plate 27 is fastened to the inner end of the conductive rod 18 by the bolts 23 inserted therethrough. Note that 27a shown in FIG. 8 is an insertion hole formed in the mounting protrusion 28 of the arc-extinguishing chamber mounting plate 27, through which the bolt 23 is inserted. Through-holes 27b for vertically penetrating bolts are formed on both sides of the arc-extinguishing chamber mounting plate 27. Arc extinguishing chambers 29 are fastened to the lower surfaces of both sides of the arc extinguishing chamber mounting plate 27 so as to cover the fixed electrodes 24 by bolts 30 inserted through the through holes 27b.

As shown in FIG. 1 and FIG.
A fixed electrode storage chamber 31 is provided for storing the electrode, and an arc extinguishing slot is provided at the lower part and the side on the bushing 17 side to allow the insertion of a movable contact blade 38, which will be described later.
A chamber 32 is provided. The fixed electrode storage chamber 3
1 is formed so that its upper end and upper side portion on the side of the bushing 16 are open to the outside. Further, in the fixed electrode storage chamber 31, the side and lower portions on the side of the bushing 17 are formed so as to communicate with the adjacent narrow arc extinguishing chamber 32. The boundary between the fixed electrode housing chamber 31 and the narrow arc extinguishing chamber 32 is formed by a movable contact blade in the fixed electrode housing chamber 31, as shown in FIG. The lower end, which is the end on the engaging direction side of 38, and the side part on the bushing 17 side, which is the side part on the engaging direction, are connected in an oblique manner.

Further, the side portion of the narrow arc extinguishing chamber 32 closer to the bushing 16 is closed along the rotation locus of a movable contact blade 38, which will be described later, and the side portion closer to the movable contact blade 38 is closed. opening 3 that allows entry of
3 is formed.

Below the fixed electrode 24, a protrusion 34 extending laterally is formed on both outer sides of the arc extinguishing chamber 29, and a protrusion 35 is provided at a position slightly above the protrusion 34. And the protrusion 35
An arc driving piece 36 formed of iron, magnets, etc. and having a U-shape in plan is disposed along the upper surface, and the protrusion 35 engages with an engaging hole 37 provided at both ends to prevent separation. It is being

A straight movable contact blade 38 is rotatably attached to the inner end of the conductive rod 18 of the bushing 17, and the contact portion 2 of the fixed electrode 24 is attached to the tip end of the movable contact blade 38.
5a and 25b so that they can be inserted. The movable contact blade 38 has a connecting shaft 39 inserted through it, and can be rotated to open and close via a drive mechanism (not shown) linked to the connecting shaft 39 by rotating the operation handle 40 outside the main case 1. It's getting old.

Inside the main body case 1, above the bushing 16 is a core mounting plate 4 made of insulating synthetic resin.
1 is inserted into a bolt 42 installed on the inner surface of the main body case 1, and is tightened and fixed by a nut 43. A cut core 4 is disposed at the bottom of the core mounting plate 41 so as to surround the outer periphery of the bushing 16.
4 is attached with screw 45. A conductive screw 46 is screwed into the lower part of the cut core 44, and its tip abuts against the inner surface of the main case 1. That is, the screw 46 allows the cut core 44 to be placed with a predetermined gap from the main body case 1 and to be grounded to the main body case 1.

Similarly, the same cut core 4 is attached to the core mounting plate 41.
A limit switch 47 is secured above 4 with a screw 48.
A movable piece 49 made of a ferromagnetic material is provided between the cut core 44 and the cut core 44 so as to be movable up and down. The movable piece 49 is always positioned upward by a spring (not shown) and controls the limit switch 47.
In addition to being in the OFF state, when an overcurrent flows due to a short circuit accident, etc., when the cut core 44 detects the overcurrent, the cut core 44 is attracted and lowered against the biasing force of the spring (not shown). and turns on the limit switch 47. By turning on the limit switch 47, the opening/closing mechanism of the switch is locked in the closed state, and the load current exceeding the capacity of the switch is not opened.

The zero-phase current transformer 50, which is commonly disposed in the bushings 17 of each phase in the main body case 1, is formed in a long track shape as shown in FIGS. It is located in

The mounting cover 51 that attaches and fixes the zero-phase current transformer 50 to the main body case 1 is made of a non-magnetic material such as stainless steel, and has mounting pieces 52 bent into an L-shape at both upper and lower ends thereof. A bushing insertion hole 54 corresponding to the bushing 17 is formed through the channel-shaped central cover portion 53 . The mounting cover 51 is the bushing 17
are inserted into the respective insertion holes 54, and the mounting pieces 5 are attached to the bolts 55 planted on the inner surface of the main body case 1.
2 is inserted and fixed by tightening the nut 56.

Then, the mounting cover 51 and the zero-phase current transformer 5
A buffer plate 57 having an L-shaped cross section and made of tracking-resistant rubber (for example, EPDM) is provided between the upper and lower parts of the zero-phase current transformer 50 and the inner surface of the main body case 1.
are arranged so that there is an intervening

Now, in the cased pneumatic switch configured as described above, when the operation handle 40 is rotated from the state shown in FIG. 1 and the movable contact blade 38 is driven to open via a drive mechanism (not shown), the movable contact blade 38 The blade 38 separates from the contact portion 25 of the fixed electrode 24. At this time, an arc A is generated between the tip of the movable contact blade 38 and the outermost side of the contact portion 25. The arc A is further extended outward as the movable contact blade 38 rotates. This arc is an alternating current, and if the direction of flow is from the back to the front of the paper in FIG. 4a, a magnetic flux α is generated around the arc A. In the drawing, the arrow shown on the drive piece 36 indicates the magnetic flux α
shows. As a result, both sides 36 of the arc drive piece 36
A magnetic flux β perpendicular to the arc A is generated between a and 36b. Therefore, according to Fleming's left-hand rule, the arc A is forcibly moved toward the bushing 16 side of the arc-extinguishing narrow chamber 32 and elongated by the magnetic force F, and the arc A is elongated.
The arc is extinguished by the arc-extinguishing gas generated in the chamber 32.

Further, when the arc flows from the front to the back of the paper in FIG. 4b, the magnetic flux α flows in the direction of the arrow shown on the drive piece 36 in the drawing. For this reason, both sides 36a of the arc drive piece 36,
A magnetic flux β perpendicular to the arc A is generated between the arcs 36b and 36b.
Therefore, according to Fleming's left-hand rule, the arc A is caused by the magnetic force F at the bushing 16 of the arc-extinguishing narrow chamber 32.
It is forcibly moved to the side and extended, and the arc extinguishing chamber 3
The arc is extinguished by the arc-extinguishing gas generated in step 2.

In addition, in the arc extinguishing chamber 29, the lower end of the fixed electrode storage chamber 31 and the side portion on the bushing 17 side are connected obliquely to increase the area of the inner surface of the narrow arc extinguishing chamber 32, so that the arc is not generated. When the arc contact area is added, the cooling arc extinguishing ability is improved, and de-ion arc extinguishing is performed efficiently, thereby extinguishing the arc A generated between the fixed electrode 24 and the movable contact blade 38. The narrow chamber 32 can be moved toward the bushing 16 side in a good manner.

In this way, in this invention, the fixed electrode storage chamber 31 is narrowed as described above, and the arc extinguishing narrow chamber 32 is further narrowed.
By widening the area of the inner surface, it has become possible to more effectively exhibit the fine arc extinguishing ability, especially the cooling arc extinguishing ability and the deionization arc extinguishing ability.

In addition, by making the movable contact blade 38 straight, it is desirable to separate the base end of the movable contact blade 38 and the arc-extinguishing chamber 29 as far as possible in order to ensure an insulation distance between the same phases, and the width of the arc-extinguishing chamber 29 (the width in the left-right direction in FIG. 1) must be as small as possible. Also, the inner surface of the arc-extinguishing fine chamber 32 must be wide, but in the fixed electrode storage chamber 31, the lower end, which is the end on the engagement direction side of the movable contact blade 38, and the side on the bushing 17 side, which is the side on the same engagement direction side, are obliquely connected in order to widen the area of the inner surface of the arc-extinguishing fine chamber 32. This makes the fixed electrode storage chamber 31 as small as possible, and the portion of the movable contact blade 38 that hangs over the fixed electrode storage chamber 31 when an arc is generated at the time of opening the circuit is small, and the movable contact blade 38
By increasing the portion of the arc-extinguishing chamber 32, the load switching capacity is improved as the size is reduced.

In addition, the tips of the bushings 16 and 17 can be arranged close to each other, and the arc generated when the bushings are opened will be surely extinguished in the narrow arc extinguishing chamber 32 on the bushing 16 side, and no sparks will occur between the bushings. There is no risk of it happening.

Incidentally, as the arc current increases, the magnetic force F also increases, so that the ability of the arc extinguishing chamber 29 can be exhibited more effectively. Therefore, the arc drive piece 36
In the case of an arc extinguishing chamber with a conventional configuration, the arc extinguishing chamber must be lengthened to increase the arc extinguishing ability, but with this invention there is no need to lengthen the arc extinguishing chamber, and the arc extinguishing chamber 29
It is also possible to make the switch as a whole more compact by reducing the space taken up by the switch.

In addition, the movable contact blade 38 and the fixed electrode 24 are directly attached to the inner ends of the conductive rods 18 of the bushings 16 and 17, and since the movable contact blade 38 is formed in a straight sword shape, it has an L-shape unlike the conventional one. Compared to a movable contact blade, when the movable contact blade 38 rotates to open and close, the rotation locus of the movable contact blade 38, that is, the space through which the movable contact blade 38 passes, can be made smaller. 24 can be increased within a limited space, thereby making it possible to make the switch lighter and more compact.

In this embodiment, the zero-phase current transformer 50 is attached around the bushing 17 via a mounting cover 51 made of a non-magnetic material such as stainless steel.
It can be firmly supported even by the surface pressure of the mounting cover 51, and local loads are prevented from being applied to the zero-phase current transformer 50.

In addition, the zero-phase current transformer 50 is mounted so as to be covered by a stainless steel mounting cover 51, and since the mounting cover 51 is grounded with the mounting piece 52 attached to the main body case 1, there is no connection between the electrode and the ground. The insulation distance can be easily set, and as described above, the zero-phase current transformer 50 can be easily attached and fixed to the main body case 1 using the attachment cover.

Furthermore, leakage current from the inner end of the bushing 17 through the outer circumferential surface can be grounded to a ground terminal 58 provided on the main body case 1 via the main body case 1 by means of the mounting cover 51.

Furthermore, the mounting cover 51 can suppress the generation of eddy current and prevent the eddy current from having an adverse effect on the zero-phase current transformer 50.

Effects of the device As detailed above, this device can reduce the rotation locus of the movable contact blade, and also enlarge the narrow arc extinguishing part near the arc generating part, increasing the arc extinguishing ability. The size of the arc extinguishing chamber itself can be reduced. This has the excellent effect of reducing the size and weight of the switch, making it an excellent invention for industrial use.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of a switch according to an embodiment of this invention, Fig. 2 is a side sectional view of the fixed electrode, Fig. 3 is a front view of the fixed electrode, Fig. 4a, b is a cross-sectional view of the arc extinguishing chamber, Fig. 5 is a schematic side view with the zero-phase current transformer installed, Fig. 6 is a front view showing the cut core installed, and Fig. 7 is the arc extinguishing chamber installed. A bottom view of the plate, FIG. 8 is a side view of the arc chamber mounting plate, and FIG. 9 is a front view of the arc chamber mounting plate. 1... Main body case, 16, 17... Bushing, 18... Conductive rod, 22... Fixed contact piece, 24
... Fixed electrode, 27 ... Arc chamber mounting plate, 29 ...
Arc extinguishing chamber, 31... fixed electrode storage chamber, 32... arc extinguishing narrow chamber, 36... arc drive piece, 38... movable contact blade, 40... operating handle, A... arc, F
...Magnetism.

Claims (1)

[Scope of utility model registration request] Bushings are penetrated and fixed to the switch case so as to face each other for each phase, and a fixed electrode is fixed to the inner end of a conductive rod inserted into one bushing, and a conductive rod inserted into the other bushing is fixed. A straight-shaped movable contact blade that is brought into contact with and separated from the fixed electrode is rotatably attached to the inner end of the rod, and an arc extinguishing chamber that covers the fixed electrode is fixed to the inner end of the conductive rod of one bushing. The arc extinguishing chamber is composed of a fixed electrode storage chamber that stores the fixed electrode, and an arc extinguishing chamber that communicates with the fixed electrode storage chamber and performs arc extinguishing. The end of the movable contact blade in the fixed electrode storage chamber on the insertion direction side and the side part on the insertion direction side are connected obliquely so that the area of the movable contact blade in the narrow arc extinguishing chamber is increased. An opening is formed in the side part to allow the movable contact blade to be inserted and opened, and an opening is formed on the outer periphery of the arc extinguishing chamber to drive the arc generated between the movable contact blade and the fixed electrode to the side surface of the arc extinguishing chamber when the movable contact blade is opened. An air switch characterized by having a letter-shaped arc drive piece.